Ion implantation generally involves accelerating of a beam of ions to a predetermined high energy to extract the desired ions for implantation from the ion beam. A high voltage, referred to as the acceleration voltage, is applied to the ion beam during acceleration to supply the energy necessary to effect beam extraction. In certain instances, the acceleration voltage may be between 5 keV to 25 keV. As a result, during ion beam acceleration certain components of the ion implantation system, including, for example, the gas box, may be at a high voltage, while other components may be at a low voltage or ground. In other modes of operation, such as the deceleration mode, it may be necessary to ground the gas box or other components of system. Selectively providing an electrical connection to a ground can be challenging, as the gas box and other components may be physically separated from a ground and conductive material, e.g. a metal wire or switch, between the gas box and the ground may cause arcing when the system is operated in the high-voltage acceleration mode.
Disclosed herein are electrical switches and methods of selectively making an electrical connection that are particularly suited for use in high-voltage environments, such as within an ion implantation system. The switches and methods of selectively switching disclosed herein permit an electrical connection to be selectively established, while concomitantly minimizing the amount of electrically conductive materials employed, thereby inhibiting arcing during high voltage operations.
In one exemplary embodiment, an electrical switch may comprise a tubular housing having a non-conductive section constructed substantially of a non-conductive material, a first electrical contact positioned proximate one end of the housing, a second electrical contact spaced apart from the first electrical contact, and a shuttle selectively displaceable within the housing between the first electrical contact and the second electrical contact. The shuttle may be biased into a first position proximate the first electrical contact in a first mode of operation and, in a second mode of operation, may be displaceable toward the second electrical contact to establish an electrical connection between the first electrical contact and the second electrical contact.
In another exemplary embodiment, an electrical switch may comprise a tubular housing constructed substantially of a non-conductive material, a first electrical contact positioned at one end of the housing, a second electrical contact positioned at a second end of the housing, a shuttle selectively displaceable within the housing between the first electrical contact and the second electrical contact, and a spring mechanism positioned within the housing and connected to the shuttle to bias the shuttle into a first position proximate the first electrical contact. The shuttle may be electrically connected to the first electrical contact and may be displaceable into engagement with the second electrical contact by pressurized gas to establish an electrical connection between the first electrical contact and the second electrical contact.
In another exemplary embodiment, an electrical switch for selectively grounding the gas box of an ion implantation system may comprise a tubular housing constructed substantially of a non-conductive material, a first electrical contact positioned at the first end of the tubular housing, a second electrical contact positioned at the second end of the tubular housing, a shuttle selectively displaceable within the tubular housing between the first electrical contact and the second electrical contact, and a spring mechanism positioned within the tubular housing and connected to the shuttle to bias the shuttle into a first position proximate the first electrical contact and within the gas box. The first end of the tubular housing may be positioned within the gas box and the second end of the tubular housing may be spaced apart from the first end across an air gap between the gas box and a ground. The first electrical contact may be electrically connected to the gas box and the second electrical contact may be electrically connected to a ground. The shuttle may be electrically connected to the first electrical contact and may be displaceable into engagement with the second electrical contact by pressurized gas to establish an electrical connection between the first electrical contact and the second electrical contact.
In a further exemplary embodiment, a method of selectively grounding a gas box of an ion implantation system may comprise providing an electrical switch comprising a tubular housing constructed substantially of a non-conductive material, a first electrical contact positioned at the first end of the tubular housing and electrically coupled to the gas box, a second electrical contact positioned at the second end of the tubular housing and electrically connected to a ground, and a shuttle selectively displaceable within the tubular housing between the first electrical contact and the second electrical contact. The shuttle may be electrically connected to the first electrical contact. The tubular housing may have a first end positioned within the gas box and a second end spaced apart from the first end across an air gap between the gas box and a ground. The method may further include positioning the shuttle proximate the first end of the tubular housing in a first mode of operation of the ion implantation system and advancing the shuttle into contact with the second electrical contact in a second mode of operation of the ion implantation system to establish an electrical connection between the first and second electrical contact.